Canister storage and launch of missiles are well known. U.S. Pat. No. 5,942,713 issued Aug. 24, 1999 in the name of Basak describes multi-missile canister holding chambers with selective firing controls. U.S. Pat. No. 6,152,011, issued Nov. 28, 2000 in the name of Ivy et al. describes a system for controlling and independently firing different types of missiles from canisters at plural launch positions.
FIG. 1a is a simplified longitudinal cross-section of a canisterized missile designated generally as 10. More specifically, the illustrated canisterized missile 10 is any type that can be fired from a vertical launch system (VLS) canister. In FIG. 1a, the canister 12 is in the form of a wall 12w defining a hollow tube or missile storage region 14 centered on a longitudinal axis 8 and lying between a missile exit or egress end 12me and a rear or bottom end (when the canister is in its vertically oriented launch position) 12be. A missile 16, defining a front end 16front and a rear 16r, is contained within storage region 14 of canister 12 in a storage state of the structure, and the missile 16 is physically guided or supported at transverse positions or planes designated 18a and 18b by a plurality of “railcar” sets 20a and 20b. Rail car set 20a lies near plane 18a during storage, and railcar set 20b lies near plane 18b. Missile 16 carries a plurality of external aerodynamically stabilizing fins designated generally as 16F. These fins are partially folded during those times when the missile 16 is within canister 12 storage region 14, but are spring-loaded to extend as the missile 16 is launched from and leaves the missile canister 12 in a second state of the structure 10.
FIG. 1b is a simplified transverse cross-section of the structure of FIG. 1a at a location, such as 1b-1b along the canister 12 of FIG. 1a, partially cut away to reveal particular details. In FIG. 1b, an elongated rail structure of a set 32 of rail structures extends along each of the inside corners 30a, 30b, 30c, and 30d of the canister 12 tube. More particularly, a rail structure 32a of set 32 extends along inside corner 30a, a rail structure 32b extends along inside corner 32b, a rail structure 32c extends along inside corner 30c, and a rail structure 32d extends along inside corner 32d. Thus, each rail structure of set 32 of rail structures is supported by two mutually adjacent walls of canister 12. FIG. 1c illustrates a simplified cross-section of one rail structure of FIG. 1b. For definiteness, the rail structure of FIG. 1c is designated 32b. As illustrated in FIG. 1c, rail 32b defines walls 32b1 and 32b2 which are affixed to adjacent walls 12w1 and 12w2 of canister 12. Rail structure 32b of FIG. 1c also defines a rail 34b in the form of a recess with overhanging lips or edges 36. Elongated rail 34 is dimensioned to accommodate a rail-engaging support of a railcar. Returning now to FIG. 1b, each of the other rail structures 32a, 32c, and 32d defines a rail similar to rail 34b of rail structure 32b. Thus, rail structure 32a defines a rail 34a, rail structure 32c defines a rail 34c, and rail structure 32d defines a rail 34d. 
In FIG. 1b, a collapsible railcar 20b2 of set 20b of railcars has its rail-engaging portion (not designated) engaged with rail 34b of rail structure 32b, and railcar 20b4 of set 20b of railcars has its rail-engaging portion (not designated) engaged with rail 34d of rail structure 32d. Rail cars 20b2 and 20b4 lie on a first diagonal relative to axis 8. Two additional railcars, which lie on the opposite diagonal, are cut away so as to reveal other details. More particularly, FIG. 1b shows two folded aerodynamic fins 40a, 40c of a set of four such fins, the other two of which are partially obscured by railcars 34b and 34d. The folded fin 40a includes a first or fixed portion 40a1 which projects generally radially relative to axis 8, and a second portion 40a2 which is folded away from the plane of portion 40a1. Folded portion 40a2 of fin 40a is spring-loaded to urge it into the same plane as portion 40a1. An interior rail or wall 42a, elongated in a direction parallel with longitudinal axis 8, maintains folded fin portion 40a2 in the folded position over a certain portion of the travel of the missile as it exits the canister. Folded fin 40c includes a first or fixed portion 40c1 which projects generally radially relative to axis 8, and a second portion 40c2 which is folded away from the plane of portion 40c1. Folded portion 40c2 of fin 40c is spring-loaded to urge it into the same plane as portion 40c1. An interior rail or wall 42c, elongated in a direction parallel with longitudinal axis 8, maintains folded fin portion 40c2 in the folded position over a certain portion of the travel of the missile as it exits the canister. Other interior rails or walls maintain the other folded fins in the folded positions.
FIG. 2a is a simplified perspective or isometric view of a railcar such as railcar 34b of FIG. 1b, partially exploded, together with a notional representation of rail structure 32b and rail 34b. The railcar of FIGS. 2a and 2b is designated generally as 200. FIG. 2b is a simplified side elevation view of the structure of FIG. 2a. As illustrated in FIGS. 2a and 2b, railcar 200 includes a rail-engaging structure or element 210 and a missile-engaging guidance and/or support structure 212, which missile-engaging structure includes a platform 214 with a missile engaging platform 216 mounted thereon. The dimensions of rail-engaging structure 210 are such that it can fit within, and slide along, a rail such as 34b of FIG. 1c. Missile engaging platform 216 bears a missile-locating button or boss 218 which registers the missile with the guide and/or support when engaged in a corresponding aperture in the missile. A linkage 220 including rear bar or element 220r and front bar or element 220f interconnects the missile-engaging structure 212 with the rail-engaging structure 210, to form or define a “four-bar linkage” 219. The term “four-bar linkage” is used freely in the domain of mechanical design and kinematics, and generally refers to a linkage including four rigid bodies (termed “bars” or “links”), each attached to two others by single joints or pivots to form a closed loop. The elements of the four-bar linkage 219 in FIGS. 2a and 2b are front and rear links 220f and 220r, and portions of rail-engaging support 210 and missile engaging platform 214 lying therebetween. The purpose of four-bar linkage 219 is to act in a manner similar to a pantograph, allowing the rail-engaging and missile-engaging platforms or structures 210, 212 to move relative to each other while remaining generally mutually parallel. A pantograph is an instrument for copying images such as plans, maps, and the like, with a fixed size reduction or augmentation. By extension, a pantograph can also be a mechanical device of generally like configuration which includes hinged links to allow motion or spacing adjustment between first and second elements joined by the links, as for example in an electric trolley or locomotive. As illustrated in FIGS. 2a and 2b, the linkage 220 includes front and rear I-beams 220f and 220r, respectively, with each I-beam taking the place of one of the links of four-bar linkage 219. Each I-beam 220r, 220f comprises a pair of flanges and a web, which may be perforated. As illustrated in the cross-section of FIG. 2c, I-beam 220f includes first and second flanges 220ff1 and 220ff2 and a web 220fw. Rear I-beam 220r is similar. Rear I-beam 220r is hingedly or rotationally affixed to rail-engaging structure 210 along an axis of rotation 2081 and is affixed to missile-engaging structure 212 along an axis of rotation 2082. Similarly, front I-beam 220f is hingedly affixed to rail-engaging structure 210 along an axis of rotation 2083 and is affixed to missile-engaging structure 212 along an axis of rotation 2084. At least one of the hinges associated with axes of rotation 2081, 2082, 2083, and 2084 of FIGS. 2a and 2b is locked against rotation in the missile storage state or condition of the canister/missile combination 10, as known in the art, by a mechanism which may be as simple as a ball-and-detent. With any one of the hinges locked, the pantograph-like four-bar linkage 219 cannot collapse. Thus, in the missile storage state of the canister/missile combination 10 of FIG. 1a, the missile 16 is coaxially held within missile storage region 14 by the combination of four railcars at each transverse location 18a, 18b. 
During missile launch, the engine (not illustrated) of the missile is started, and the entire missile moves toward the missile egress end 12me of canister 12 of FIG. 1a, initially guided or supported by the railcars, moving on their respective rails. At a selected point along their travel toward the missile egress end of the canister, the leading set 20b of railcars reaches a stop which prevents further motion toward the missile egress end. Concurrently with reaching the stop, an unlocking mechanism unlocks the hinge or hinges of the four railcars of set 20b, as by disengaging a ball from a detent, all as known in the art. The inertia of the moving railcar and of the still-momentarily-attached missile causes the missile-engaging platform 212 to continue to move toward the egress end of the canister, while the rail-engaging platform is stopped. With the hinge(s) unlocked, the railcar begins to collapse, as illustrated in FIG. 3a, where the arrow 310 indicates the motion of the missile-engaging platform 212 relative to the stopped rail-engaging support 210. The direction of motion of the rear linkage 220r is indicated by the arrow 312. When the missile-engaging structure 212 starts to collapse toward the railcar rail-engaging support 210, the missile 16 is released, at least at that cross-section. A moment later, the missile-engaging structure 212 of the railcar collapses onto the still-stopped rail-engaging structure 210, as illustrated in FIG. 3b. At this time, the movement of the railcar components toward the missile egress end of the canister has stopped. The speed and inertia of the vertically-moving missile-engaging structure 212 and of the swiveling links 220r and 220f, in conjunction with the elasticity of the structural members, tends to cause the missile-engaging structure to rebound upward and in a retrograde direction, as illustrated by arrow 230 in FIG. 3c. It has been found that recoil or rebound of the missile-engaging portion of the railcar occurs at times at which the fins of the missile are in the vicinity. It is known that such touching can affect the orientation of the missile as it leaves the canister, a condition affecting the “tip-off” angle. Also, the rebounding missile-engaging portions of the railcar might conceivably damage the fins, although this has not been seen. FIG. 3d illustrates a portion of a canisterized missile 16 with its fins 16F traveling in the direction of arrow 308 relative to the stopped railcar 200. At the moment illustrated in FIG. 3a, the rail-engaging support 210 has reached rail stop 392, missile-engaging railcar platform 212 is moving in the direction indicated by arrow 230, and the lower fin 16Fl of the missile is about to come into contact with the missile-engaging platform element 212 of railcar 200.
In one embodiment, the links of the railcars are spring-loaded to aid in quickly moving the missile-engaging structure out of the way of the missile. The spring loading tends to increase the rebound.
Improved or alternative missile launch structures are desired.